Benchmark: get first string segment: split vs slice

Script Preparation code:

var name = 'foo:bar'

Tests:

slice
name.split(0, name.indexOf(':'))
split
name.split(':')[0]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
split

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
slice	3609126.2 Ops/sec
split	4196905.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):

LLMs can make mistakes. Check important info.

### Benchmark Overview

This benchmark compares the performance of two different methods for extracting the first segment of a string in JavaScript: using the `split` method versus using the `slice` method. The benchmark is designed to assess which approach is faster in terms of execution speed.

### Test Cases

1. **Using `slice`:**
   - **Benchmark Definition:** `name.split(0, name.indexOf(':'))`
   - **Test Name:** `slice`
   - **Description:** This test attempts to use the `split` method starting from index `0` up to the position where the colon (`':'`) is found. Technically, the intention here might have been to extract the substring, but the provided code will not work as intended because the `split` function doesn't take an index range as arguments; rather, it is used to divide a string into an array based on a specified delimiter, which contrasts with what might be expected from using `slice`.

2. **Using `split`:**
   - **Benchmark Definition:** `name.split(':')[0]`
   - **Test Name:** `split`
   - **Description:** In this test, the `split` method is correctly used to split the string `name` by the delimiter `':'` and then retrieve the first element of the resulting array (which is the substring before the colon).

### Performance Results

From the results, we can see:
- The `split` method achieved **4,196,905** executions per second.
- The `slice` method (incorrectly coded as such) reached **3,609,126.25** executions per second.

### Pros and Cons of Approaches

1. **Using `split`:**
   - **Pros:**
     - Clear and straightforward syntax for dividing a string based on a delimiter.
     - Returns an array of all segments, allowing more flexibility if needed (e.g., accessing other segments).
   - **Cons:**
     - May be slightly less performant than other methods when not specifically needed for splitting into multiple segments.

2. **Using `slice`: (as intended commentary)**
   - **Pros:**
     - Works directly with indexing to extract substrings, which can be very efficient for simple cases.
   - **Cons:**
     - Improper implementation in this case as it does not adapt correctly for the specific use case of extracting only up to a delimiter.
     - The method itself is not optimally set for the intended operation (splitting by a delimiter), leading to potential confusion.

### Other Considerations

- Using the `split` method is generally more readable for those who need to separate strings at specific delimiters, making it a preferred choice in most cases.
- If only a single substring is required, and the format is consistent, `slice` can be a better choice if implemented correctly.
- The benchmark consistently highlights how minor variations in implementation can significantly impact performance and correct functionality.
  
### Alternatives

Beyond `split` and `slice`, there are other alternatives such as:

- **Regular Expressions:** Using regex for more complex string extraction requirements. For instance, `name.match(/^(.*):/)[1]` would directly capture the first segment before the colon as well.
- **String.prototype.indexOf & String.prototype.substring:** Combining `indexOf` with `substring` could also yield efficient results, like `name.substring(0, name.indexOf(':'))`.

### Conclusion

The benchmark effectively illustrates performance differences between common string manipulation methods in JavaScript. While the `split` method is typically more intuitive for handling delimiters, implementing accurate code is crucial for achieving optimal results. Understanding these distinctions helps software engineers make informed decisions about string manipulations in their applications.

Related benchmarks:

get first string segment: split vs slice (version: 1)

Javascript split vs slice performance

Comparing performance of: slice vs split

Created: 3 months ago by: Guest

Jump to the latest result

slice

split

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 3 months ago):